Coordinated control valve



March 31, 1942. THQMPSON v 2,278,003

CO -ORDINATED CONTROL VALVE Filed June 23, 1939 75 INVENTOR' PARKE H.Tr1oMPsoN ATTORNEY Patented Mar. 31, 1942 UNITED STATES PATENT OFFICE COORDINATED CONTROL VALVE Parke H. Thompson, Millville, N. J. Application June 23, 1939, Serial No. 280,721

17 Claims.

This invention relates to a certain new and useful improvement in co-ordinated control valves adapted particularly, though not exclusively, fOr use in conjunction with refrigerating systems and the like.

My invention has for its primary objects the provision of a valve of the type statedwhich is compact in size and economical in construction, which as a unitary structure combines all the necessary and essential features for maintaining accurate and precise control over the system in conjunction with which it is installed, which maintains accurate recirculating control of the liquid supply to the refrigerating system responsive to the rate of return flow thereof, which precisely and accurately maintains desired conditions of back-pressure, which separates the returning refrigerant into its liquid and gaseous components for recirculation and return to the compressor, respectively, which may be assembled and fabricated with ease and facility, and which is highly eflicient in the performance of its intended functions.

And with the above and other objects in view, my invention resides in the novel features of form, construction, arrangement, and combina tion of parts presently described and pointed out in the claims.

In the accompanying drawing- Figure 1 is a longitudinal sectional view of a control valve constructed in accordance with and embodying my present invention;.

Figure 2 is a transverse sectional view of the valve, taken approximately alongthe line 2--2, Figure l; and

Figure 3 is a diagrammatic view illustrating the valve in operative association with a refrigerating system.

Referring now in more detail and by reference characters to the drawing, which illustrates a preferred embodiment of my invention, the control valve, generally designated A, comprises a suitably elongated open-end tubular or cylindrical shell I constructed preferably of metal and exteriorly provided adjacent its upper end margin with an annular attachment flange 2 having an annular series of spaced threaded apertures 2' for retentively receiving stud-bolts 3 disposed through apertures 3' in a centrally apertured end-plate 4 disposed fiatwise over the one or upper end of the shell I and sealed upon the ring 2 by means of a suitable gasket 4'.

Adjacent its upper end, the shell I is transversely pierced and provided with an annular flange 5 for hermetically sealed threaded engagement with a seating sleeve 6 of a back-pressure regulator 1' including a housing 1. Peripherally secured in and extending transversely across the housing I, is a diaphragm 3 provided upon its outer face with an external pressure plate 9 held in concentrically aligned, laterally shiftable position by a ring I0 and biased by a compression spring II abuttingly seated at its outer end within a dished spring-retaining washer I2 rotatively mounted on a pin-like projecting end I'3 of an adjustment screw I4 threadedly mounted in and projecting through the outer end wall I5 of the housing I and provided on its outer end with a cap nut I6, all as best seen in Figure 1 and for purposes presently fully appearing.

Centrally of its inner face, the diaphragm 8 is provided with an internal pressure plate I! positioned and counter-biased by an annular spring I8 and provided with a preferably integrally formed tubular extension I 9 projecting axially inwardly through, and. being preferably of rectangular cross-section with a diagonal dimension substantially equal to the diametral size of, the housing sleeve or coupling 6, the extension I9 having a transverse end wall 20 for abutting engagement with an axially projecting valve pin 2|, also as best seen in Figure l and for purposes presently appearing.

Welded or otherwise permanently fixed in the end wall 4, is a tubular member 22 axially bored or machined in the provision of an inwardly converging Venturl neck or diffuser 23 tapering into a more or less straight sided throat or constriction 24 and at its inner end being flared sharply outwardly, as at 25, in the provision of a valve seat 26. The member 22 is further provided in its outer face with an axially extending slot 21 opening at one end upon the oblique face 25 and terminating a short distance from the wall engaging end of the member 22, all as best seen in Figure 1 and for purposes presently fully appearing.

Formed preferably integrally with the member 22 and extending radially inwardly partially across the Venturi throat 23, is a substantially rigid supporting boss 23 provided at its Outer end with a somewhat egg-shaped or streamlined enlargement 29 having a bore 30 in co-axial alignment with the constriction 24. The boss 28 and the body of the insert 22 are provided with intersecting drill holes 3|, 32, conventionally plugged, as at 33 and 34, in the provision of normally closed passages, the drill hole 32 at its inner end and in its outer side wall being provided with an aperture 35 for receiving an annular pilot valve seat 36 positioned for seating co-operation with the pointed end of the valve pin 2|.

Welded or otherwise permanently fixed in the bore 38 and extending inwardly through and projecting a substantial distance beyond the constriction 24, is a tubular stem 31 having an aperture 38 for communication with the drill-hole 3| and having in its outer end a nozzle-shaped tip member 39 externally contoured as a continuation of the streamlining end enlargement 29 and provided with an axially extending relief bore 48 of relatively small diameter, all as best seen in Figure 1 and for purposes presently fully appearing.

Shiftably mounted on the stem 31, is a seatsupporting sleeve 4| having a longitudinal vent slot 4| opening on the downstream side of the Venturi throat 24 The sleeve 4| is positic red for extension through and beyond the constriction 24 and provided at its projecting end with an annular cup-like collar 42 having a bottom wall 43 provided with an outwardly projecting annular shoulder 44 and an opposed end face 45 having a short retention flange 46 for engagement with an annular valve plug 41 sized for valve closing co-operation with the valve seat 26, the exposed faces of the sleeve 4|, the valve plug 41, and the collar 42 being of somewhat paraboloidal or streamlined shape, all as best seen in Figure 1 and for purposes presently fully appearing.

Welded or otherwise hermetically secured upon the inwardly presented transverse face 48 of the collar 42, is a cylindrical bellows or Sylphon 49 provided at its other end with an inwardly depressed frusto-conical washer 58 having a hubportion welded or otherwise permanently fixed to the tubular stem 31 adjacent its outer end, the portion 5| being diametrally reduced along its outer face, as at 52, for retentively engaging one end of a compression spring 53, in turn, at its other end seatingly disposed around the shoulder 44 of the collar 42 in the formation of an inner expansible chamber a.

Marginally welded or otherwise hermetically secured to, and suitably mortised in, the outer face of the collar 42, is 9. preferably metallic ovicapsular bulb 54 having an external contour which is a smoothly curved continuation of the streamlined-shaped collar 42 and valve plug 41 and being along its inner face spaced substantially outwardly from the Sylphon 49, dividing the interior of the valve A into an enclosed expansion chamber b and an annularor so-called separation chamber 0. The bulb 54 extends substantially beyond the end of the stem 31 and is provided with a transversely extending end casting 55 having a centrally disposed tubular guide sleeve 56 internally sized for snug-fitting slidable engagement over the end portion of the stem 31 and having a pair of diametrally opposed radial apertures 51 providing communication between the chamber b and the interior of the valve stem 31.

Riveted or otherwise fixed upon the bottom face of the slot 21, is a hairpin spring 58 having a fiat leaf 59 embracingly disposed around, and by a dished spring washer 68 resiliently secured to, the pin 2|. At its free end, the spring leaf 59 is provided with a pair of spaced parallel inwardly projecting ears 6| having a transversely extending pin 62 for rotatively supporting a roller 63 slidably engaging the outwardly presented paraboloidal surface of the collar 42, all as best seen in Figure 1 and for purposes presently fully appearing.

- Welded or otherwise hermetically sealed upon the outer face of the shell I adjacent its upper end and projecting tangentially through the shell wall, is a fitting 64 opening into the annular or separating chamber c and provided at its outer end with a flange 65 for conventional connection with an inlet line 66, all as best seen in Figure I 2 and for purposes presently fully appearing.

Fixed upon and extending annularly around the lower extremity of the insert member 22, is a tubular baiile 61 diametrally enlarged, as at 68, and provided with a downwardly depending skirt 69 spaced a substantial distance below the plane of the fitting 64 and provided with a plurality of annularly spaced vanes 10 projecting radially outwardly from the skirt 69 'and being deflected arcuately downwardly for imparting a whirling movement to the gas liquid mixture passing therethrough, all as best seen in Figures 1 and 2 and for purposes presently fully appearing.

At its lower end, the shell I is externally provided with an annular attachment flange or ring 1| provided with a plurality of annularly spaced apertures 1| for retentively receiving stud-bolts 12 disposed through apertures 12' formed in a bottom plate 13 extending transversely across the lower open end of the shell I and sealed upon the flange or ring 1| by means of an annular gasket 14.

The plate 13 is centrally provided with an internally threaded aperture 15 for adiustably receiving a valve nozzle 16 having a valve orifice 11. Fixed upon the outer face of the end plate 13 in concentric alignment with the aperture 15, is a connection collar 18 arranged for connection in any conventional manner to a supply line 19.

Welded or otherwise permanently fixed upon the upwardly presented face of the end plate 13 and fitting snugly within the lower portion of the shell I, is an inner supporting shell 88 provided at its upper end with a horizontally extendlng base plate 8| provided in its upper face with a recess 82 having a bottom wall 83 provided with a centrally disposed aperture 84. Disposed on the upper face of the base plate 8|, is a diaphragm 85, which extends across the recess 82 and is centrally provided with an aperture 86 for embracing engagement around the hub portion 81 of a pressure plate 88 disposed fiatwise concentagically upon the upper face of the diaphragm Also disposed upon the upper face of, and in peripheral registration with, the diaphragm 85, is a cap 89 provided centrally on its under face with a shallow annular recess 98 of relatively large diameter and having a bottom wall 9| centrally apertured, as at 92, and extending in spaced parallel relation above the diaphragm 85 in the formation of a pressure actuating chamber 1).

' On its under face, the diaphragm 85 is provided with a concentric pressure plate 93 centrally apertured for snugly embracing the downwardly depending hub portion 81 of the pressure plate 88 and being biased upwardly by an annular spring washer 94 seated around its outer peripheral margin against the side wall of the recess 82. Adjacent its outer peripheral margin, the plate 8| is apertured and provided with a vertically extending tube 95 bent over at its upper end and provided with a restricted port or orifice 96, all as best seen in Figure 1 and for purposes presently fully appearing.

Welded or otherwise suitably fixed upon the under face of the base plate 8|, is an elbow tube 91 extending radially inwardly to the center of the shell I and bent downwardly in the formation of a longitudinal leg 98 terminating in a plane spaced at short distance from the valve orifice 11 and being interiorly provided with a tubular insert shell 99 axially bored in the provision of a Venturi constriction I00. At its bend, the elbow tube 91 is provided with an aperture IOI for shiftably accommodating a tubular valve stem I02 extending axially downwardly through the Venturi constriction I and the orifice 11, the stem I02 at its lower. extremity being provided with an annular valve plug I03 for closureforming or seated engagement within the orifice 11.

At its upper end, the stem I 02 projects through the aperture IOI and is mounted in and projects through the hub 81 of the upper pressure plate 88 and the aperture 92 of the cap wall 9|. It should be pointed out in this connection that the aperture 92 is of slightly greater diametral size with respect to the projecting end of the valve stem I02, so as to allow for a slight amount of leakage from the chamber p, all as best seen in Figure l and for purposes presently fully appearing.

Welded or otherwise permanently fixed at its lower end upon the upper face of the base plate 8| and extending perpendicularly upwardly therefrom, is a channel-shaped upright or supporting post I00 having a pair of opposed flanges I05 preferably integrally connected by a transversely extending web member I06. Mounted in and extending between the flange members E05 adjacent the upper end of the upright I00, is a pintle I01 for swingable engagement with a mounting lug I08 of a float ball I09 substantially smaller in diametral size than the base plate 05, all as best seen in Figures 1 and 2 and for purposes presently fully appearing.

Swingably suspended at its upper end from the mounting lug I00 in outwardly spaced relation to the pintle I01, is a link M0 pivotally connected at its lower extremity to the outer end of an actuating lever I I I, in turn, pivotally mounted adjacent its opposite end upon a fulcrum pin II2 supported in a fulcrum plate H3 welded on, and extending horizontally across the upper projecting end of, the valve stem I02, the lever III being preferably integrally provided with a horizontally disposed web-portion H0 projecting beyond the fulcrum pin H2 and abuttingly engaging the upper end of a valve pin H5 shiftably mounted in the upper end of the valve stem I02 for co-operation with a tubular seat forming insert H6 welded or otherwise rigidly secured within the valve stem I02.

At its upper end, the valve pin I is operably connected with one leg of a small hairpin spring M1 for normally urging the pin H5 upwardly against the web II4 of the actuating lever II I. Just above the upper end of the seat-forming insert II6, the valve stem I02 is provided with a pair of diametrally opposed pilot ports IIO opening into the chamber p, all as best seen in Figure l and for purposes presently fully appearmg.

The inner shell 80 and the outer shell I are further provided with coinciding apertures H9 in registration with the open horizontally disposed end of the bent tube 91 and opening into a connection collar I welded or otherwise rigidly secured upon the outer face of the shell I for connection in any conventional manner to a pipe line I2I, all as best seen in Figure 1 and for purposes presently fully appearing.

Welded or otherwise hermetically sealed upon the upper face of the end plate 4 in registration with the mouth of the Venturi throat 23, is a coupling collar I22 for connection in any conventional manner to a return or suction line I23.

Although control valves constructed in accordance with my present invention may be employed in a wide variety of installations, I have for purposes of illustration chosen to describe its use and operation in connection with a refrigerating system including a compressor B, a liquid condenser-receiver C, and a kinetic evaporator D. The valve A is connected through the intake or supply line 19 to the condenser-receiver C and through the return line I23 to the suction or intake side of the compressor B. The pipe line I2I is connected to the intake side of the evaporator D and the return line 66 finally connected to the outlet side of the evaporator D, all as best seen in Figure 3.

Under starting conditions, there will be a relatively small amount of liquid return from the evaporator D; hence, the float ball I09 will drop to its lowest position, swinging the link I I0 downwardly and pivoting the actuating-lever I so as to permit upward shifting movement of the valve pin II5. As the valve pin II5 moves upwardly, a relatively small amount of high pressure refrigerant will flow through the pilot ports I I8 into the chamber p, depressing the diaphragm and, at the same time, shifting the valve stem I02 downwardly and moving the valve plug I03 out of seated engagement, thereby permitting a supply of liquid refrigerant to flow upwardly through the Venturi constriction I00 and the elbow tube 91 into the pipe line I2I for delivery to the evaporator D.

The evaporated liquid gaseous refrigerant mixture returning from the evaporator D through the line I56 is forced to pass between the vanes 10 by which it is centrifugally separated into its liquid and gaseous components. The unevaporated liquid refrigerant flows downwardly along the inner side faces of the shell I upon and through the port 96 and the tube 95 into the interior of the inner shell 80, whence it is drawn by the Venturi constriction I00 into the elbow tube 91 for recirculation with the incoming fresh refrigerant.

If, at any time, the rate of return flow of liquid refrigerant increases beyond the selected volume which the port 96 has been sized to accommodate, the excess volume of returning refrigerant will build up a substantial head of returned liquid refrigerant above the base plate III. As the level of this liquid refrigerant rises, the float ball I09 and its associated link IIO will be shifted upwardly, reversely pivoting the actuating lever I II and shifting the valve pin II5 toward closed position for either restricting or entirely cutting off the supply of high-pressure refrigerant to the chamber p, thereupon permitting the diaphragm 85 to be returned to normal position under the force of the annular spring 94, thereby shifting the valve stem I02 upwardly and throttling or entirely cutting off the flow of fresh liquid refrigerant through the orifice 11.

As long as the temperature of the evaporator Dis at or below the desired temperature for which the back-pressure regulator r is set, the

annular valve plug 41 will remain in seated position under the force of the tension spring 59.

When, however, the temperature rises materially beyond the desired point, the back-pressure will be sufilciently increased so as to shift the diaphragm 8 and its associated pilot valve pin 2| outwardly, admitting relatively high-pressure gaseous refrigerant to the chamber b and shifting the bulb 54 and its associated annular valve 'plug .41 downwardly out of seated engagement the valve pin 2| by the difierence between theforce of the spring II and the pressure on the pressure plate [1, as more particularly and fully described and pointed out in my copending application Serial No. 280,722. In addition, the fiow control mechanism is also automatically self-compensating as more particularly and fully disclosed in my copending application Serial No. 280,720. Thus it will be seen that all of the control elements of the present valve are so arranged and constructed that cycling or wild hunting, which results from valve over-travel, is entirely eliminated.

It should be understood that changes and modifications in the form, construction, arrangement, and combination of the several parts of the valve may be made and substituted for those herein shown and described without departing from the nature and principle of my invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is- 1. A control structure for use in regulating apparatus adapted to receive a supply-flow of liquid and discharge a return fiow containing varying proportions of liquid and gas, said structure comprising first valve means, second valve means, means for receiving the return fiow and separating the same into liquid and gaseous components, means responsive to the pressure of the gaseous component for actuating the first valve means, and means responsive to the rate of means responsive to the pressure of the gaseous component for actuating the first valve means whereby to maintain a predetermined pressure within the chamber, means responsive to the rate of return of the liquid component for actuating the second valve means, and means associated with the second valve means for withdrawing the return liquid from the chamber and introducing it into the supply-flow for recirculation.

4. A control structure for use in regulating apparatus adapted to receive a supply-flow of liquid and discharge a return flow containing varying proportions of liquid and gas, said structure comprising a chamber, first and second valve means, means within the chamber for receiving the return fiow and separating the same into liquid and gaseous components, pilot valve means responsive to the pressure of the gaseous component for actuating the first valve means, means responsive to the rate of return of the liquid component for actuating the second valve means, and Venturi means associated with the second valve means for withdrawing the return liquid from the chamber and introducing it into the supply-flow for recirculation.

5. A control structure for use in regulating apparatus adapted to receive a supply-flow oi liquid and discharge a return fiow containing return of the liquid component for actuating the second valve means.

2. A control structure for use in regulating apparatus adapted to receive a supply-flow of liquid and discharge a return flow containing varying proportions of liquid and gas, said structure comprising first valve means, second valve means, means for receiving the return fiow and separating the same into liquid and gaseous components, means responsive to the pressure of the gaseous component for actuating the first valve means, means responsive to the rate of return of the liquid component for actuating the second valve means, and means associated with the second valve means for re-inducting the liquid component into the supply flow.

3. A control structure for use in regulating apparatus adapted to receive a supply-flow of liquid varying proportions of liquid and gas, said structure comprising a chamber, first and second valve means, means within the chamber for receiving the return fiow and separating the same into liquid and gaseous components, pilot valve and discharge a return flow containing varying proportions of liquid and gas, said structure comprising first valve means, second valve means, means for receiving the return fiow and separating the same into liquid and gaseous components, means responsive to the pressure of the gaseous component for actuating the first valve means, means operatively associated with the first valve means for damping the movement of said valve means for substantially preventing over-travel, and means responsive to the rate of return of the liquid component for actuating the second valve means.

6. A control structure for use in regulating apparatus adapted to receive a supply-flow of liquid and discharge a return flow containing varying proportions oi? liquid and gas, said control device comprising first valve means, second valve means, means for receiving the return fiow and separating the same into liquid and gaseous components, means responsive to the pressure of the gaseous component for actuating the first valve means, means responsive to the rate of return of the liquid component for actuating the second valve means, and means operatively associated with the second valve means for damping the movement of said valve means for substantially preventing over-travel.

7. A control structure for use in regulating apparatus adapted to receive a supply-flow of liquid and discharge a return fiow containing varying proportions of liquid and gas, said structure comprising first valve means, second valve means, means for receiving the return fiow and upper and lower end walls respectively provided with outlet and inlet connections,. an intermediate transverse member disposed between the end walls for dividing the control into upper and lower chambers, auxiliary inlet means opening to the upper chamber for inducting a return flow of liquid and gas from the refrigeration system into said upper chamber, auxiliary outlet means opening to the lower chamber, a tubular insert mounted co-axially in the upper chamber and internally contoured in the provision of a Venturi constriction. a boss formed integrally with the insert and projecting radially into the difiuser of the Venturi constriction, a tubular valve stem rigidly mounted in the boss and extending axially through the Venturi constriction, a valve plug shiftably mounted on the stem, means mounted on the stem and operatively connected to the plug for forming an expansible chamber around an end of the stem for shifting the plug into and out of seated engagement in the Venturi constriction, said means being in communication with the interior of the valve stem and said stem being, in turn, connected to the upper chamber, pilot valve means operatively associated with the valve stem for controlling the flow of refrigerant to the expansible chamber, a tube disposed in the lower chamber for conducting supply liquid from the inlet connection to the auxiliary outlet means, and secondary valve means actuable responsive to the rate of return of the liquid component in the return flow entering the upper chamber through the auxiliary inlet in the upper chamber for controlling the fiow of liquid through the tube.

9. A unitary control for use with a refrigerating system comprising a tubular shell having upper and lower end walls respectively provided with outlet and inlet connections, an intermediate transverse member disposed between the end walls for dividing the control into upper and lower chambers, auxiliary inlet means opening to the upper chamber for inducting a return flow of liquid and gas from the refrigerating system into said upper chamber, auxiliary outlet means opening to the lower chamber, a tubular insert member mounted co-axially in the upper chamber and internally contoured in the provision of a Venturi constriction, a boss formed integrally with the insert member and projecting radially into the diffuser of the Venturi constriction, a tubular valve stem rigidly mounted in the boss and extending axially through the Venturi constriction, a valve plug shiftably mounted on the stem, means mounted on the stem and operatively connected to the plug for forming an expansible chamber around an end of the stem for shifting the plug into and out of seated engagement in the Venturi constriction, said means being in communication with the interior of the valve stem and said stem being connected to the upper chamber, pilot valve means operatively associated with the valve stein for controlling the flow of refrigerant to the expansible chamber, a tube disposed in the lower chamber for conducting supply liquid from the inlet connection to the auxiliary outlet means, secondary valve means actuable responsive to the rate of return of the liquid component in the return flow entering the upper chamber through the auxiliary inlet in the upper chamber for controlling the flow of liquid through the u tube, means for conducting return liquid from the upper chamber to the lower chamber, and

means for re-inducting said return liquid into the tube.

10. A unitary control for use with a refrigerating system comprising a tubular shell having upper and lower end walls respectively provided with outlet and inlet connections, an intermediate transverse member disposed between the end walls for dividing the control into upper and lower chambers, auxiliary inlet means opening to the upper chamber for inducting a return flow of liquid and gas from the refrigerating system into said upper chamber, auxiliary outlet means opening to the lower chamber, a tubular insert member mounted co-axially in the upper chamber and internally contoured in the provision of a Venturi constriction, a boss formed integrally with the insert member and projecting radially into the diffuser of the Venturi constriction, a tubular valve stem rigidly mounted in the boss and extending axially through the Venturi constriction, a valve plug shiftably mounted on the stem, means mounted on the stem and operatively connected to the plug for forming an expansible chamber around an end of the stern for shifting the plug into and out of seated engagement in the Venturi constriction, said means being in communication with the-interior of the valve stem and said stem being connected to the upper chamber, pilot valve means operatively associated with the valvestem for controlling the flow of refrigerant to the expansible chamber, a tube disposed in the lower chamber for conducting supply liquid from the inlet connection to the auxiliary outlet means, secondary valve means actuable responsive to the rate of return of the liquid component in the return flow entering the upper chamber through the auxiliary inlet in the upper chamber for controlling the flow of liquid through the tube, means for conducting return liquid from the upper chamber to the lower chamber at a relatively constant rate of flow, and means for re-inducting said return liquid into the tube.

11. A control structure for use in regulating apparatus adapted to receive a supply-flow of liquid and discharge a return flow containing varying proportions of liquid and gas, said structure comprising a tubular shell having opposed end walls, an intermediate wall disposed between the shell end walls for dividing the shell into upper and lower chambers, first valve means in the upper chamber for controlling the back-pressure, second valve means in the lower chamber for controlling the supply-flow, and means in the upper chamber for actuating the second valve means responsive to the quantity of liquid in the return flow.

12. A control structure for use in regulating apparatus adapted to receive a supply-flow of liquid and discharge a return flow containing varying proportions of liquid and gas, said structure comprising a tubular shell having opposed end walls, an intermediate wall disposed between the shell end walls for dividing the shell into upper and lower chambers, first valve means in the upper chamber for controlling the back-pressure, means associated with the first valve means for separating the return flow into liquid and gaseous components, second valve means in the lower chamber for controlling the supply-flow, and means in the upper chamber for actuating the second valve means responsive to the quantity of liquid in the return flow.

l3. A unitary control for use with a refrigerating system having an evaporator adapted to receive a supply flow of liquid refrigerant and discharge a return flow of mixed gaseous and liquid refrigerant, said control comprising a tubular shell having transverse closure-forming end walls, .an outlet connection mounted centrally of and extending through one of said walls, a tubular insert mounted upon said end wall and extending co-axially into the shell as a continuation of the outlet connection and being open at its inner end for communication with theinterior of the shell, a return line connection extending through the shell wall and opening into the annular space between the insert and the shell, centrifugal separator means mounted annularly about the insert for separating the return refrigerant into liquid and gaseous components, a valve plug operably mounted for co-operation with the insert, and pressure-responsive shiftable means operably connected to said plug for shifting the same into and out of seated engagement in the insert responsive to variations in the pressure of the gaseous component. 4

14. A unitary control for use with a refrigerating system having an evaporator adapted to receive a supply flow of liquid refrigerant and discharge a return flow of mixed gaseous and liquid refrigerant, said control comprising a tubular shell having transverse closure-forming end walls, an outlet connection mounted centrally of and extending through one of said walls, a tubular insert mounted upon said end wall and extending co-axially into the shell as a continuation of the outlet connection and being open at its inner end for communication with the interior of the shell, 9. return line connection extending through the shell wall and opening into the annular space between the insert and the shell, centrifugal separator means mounted annularly about the insert for separating the return refrigerant into liquid and gaseous components, a valve plug operably mounted for co-operation with the insert, means actuated by the pressure of the gaseous component and operatively connected to said plug for shifting the same into and out of seated engagement in the insert, and pilot valve means responsive to variations in pressure of said gaseous component for controlling the flow of gaseous component to the plug-actuating means.

15. A unitary control for use with a refrigerating system having an evaporator adapted to receive a supply flow of liquid refrigerant and discharge a return flow of mixed gaseous and liquid refrigerant, said control comprising a tubular shell having transverse closure-forming end walls, an outlet connection mounted centrally of and extending through one of said walls, a tubular insert mounted upon said end wall and extending co-axially into the shell as a continuation of the outlet connection and being open at its inner end for communication with the interior of the shell, a return line connection extending through the shell wall and opening into the annular space between the insert and the shell, centrifugal separator means mounted annularly about the insert for separating the return refrigerant into liquid and gaseous components, a valve plug operably mounted for co-operation with the insert, means actuated by the pressure of the gaseous component and operatively connected to said plug for shifting the same into and out of seated engagement in the insert, pilot valve means responsive to variations in pressure of said gaseous component for controlling the flow of gaseous component to the plug-actuating means, a supply line extending through the shell for conducting a supply of refrigerant to the evaporator, and means in the shell for controlling said flow of supply liquid responsive to the rate of flow of liquid from the separator. a

16. A unitary control valve for use with a device adapted to receive a supply flow of fluid and discharge against a given back-pressure a return flow containing a quantity of liquid, said valve comprising back-pressure regulating means, means for abstracting the liquid from the return flow, metering means for measuring the rate of return flow of the abstracted liquid and moving mechanically responsive to variations in such rate of flow, valve means actuable responsive to movement of said meter--v ing means for throttling the supply flow, and

means for recirculating such abstracted liquid in an amount which varies as a function of the back-pressure established by the back-pressure regulating means and the rate of supply flow established by the throttling means.

- 17. A unitary control valve for use with a device adapted to receive a supply of fluid and discharge against any given back-pressure, a return flow of fluid having a liquid component, said valve comprising back-pressure regulating means, means for abstracting the liquid component from the return flow, metering means moved by said liquid component in such a- 'manner that the degree of movement is a measure of the amount of variation in the rate of flow of said liquid component, means actuable'responsive to movement of the metering means for throttling the supply flow and thereby establishing an inlet pressure, and means for recirculating such liquid component in an amount which varies as a function of the back-pressure and the rate of supply flow.

PARKE H. THOMPSON. 

